*Related video above: What are PFAS, so-called ‘forever chemicals’?

(WHTM) — You have probably seen silica gel packets in such places as shoeboxes, dried food and even bubble wrap. It’s a white packet that always has the warning “Do Not Eat” on it.

So what is silica gel and what is it used for?

Silica gel packets are used to keep products at the correct humidity. These little packets take in moisture when there is too much of it in products or in the air. But, if the air gets too dry, they can re-release some of the water it has collected.

Silica gel, according to Discover Magazine, is categorized as a desiccant, which is used to create or sustain a state of dryness in its vicinity. These substances are used to keep goods dry in situations where excess moisture can either damage or lower the quality of the product in which they are placed.

The packets work by having little pellets of water and silica, which happens to be the main component in sand. The magazine states that the little pellets have sponge-like structures. All the gaps between the molecules are what cause the gel to hold on to water so well.

If moist air comes in contact with the packet, the droplets will slowly build up and will eventually make contact with the pellets inside the packet. Once this happens, the water will hold onto the silica gel tightly while filling the internal structure of each pellet inside the packet.

The magazine stated that silica gel is nontoxic, but you should not even try to munch on it. Though it may not get you sick, the Illinois Poison Control Center says the biggest risk is choking on the packet. This is because people may think it is part of the packaged food.

Since there can be confusion sometimes over what exactly is in the packet, it is recommended to call poison control if someone swallows a desiccant packet, just to be safe.